# Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
# Spack Project Developers. See the top-level COPYRIGHT file for details.
#
# SPDX-License-Identifier: (Apache-2.0 OR MIT)

from __future__ import print_function

import os
import re

import llnl.util.tty as tty
from llnl.util.filesystem import mkdirp

import spack.repo
import spack.stage
import spack.util.web
from spack.spec import Spec
from spack.url import (
    UndetectableNameError,
    UndetectableVersionError,
    parse_name,
    parse_version,
)
from spack.util.editor import editor
from spack.util.executable import ProcessError, which
from spack.util.naming import (
    mod_to_class,
    simplify_name,
    valid_fully_qualified_module_name,
)

description = "create a new package file"
section = "packaging"
level = "short"


package_template = '''\
# Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
# Spack Project Developers. See the top-level COPYRIGHT file for details.
#
# SPDX-License-Identifier: (Apache-2.0 OR MIT)

# ----------------------------------------------------------------------------
# If you submit this package back to Spack as a pull request,
# please first remove this boilerplate and all FIXME comments.
#
# This is a template package file for Spack.  We've put "FIXME"
# next to all the things you'll want to change. Once you've handled
# them, you can save this file and test your package like this:
#
#     spack install {name}
#
# You can edit this file again by typing:
#
#     spack edit {name}
#
# See the Spack documentation for more information on packaging.
# ----------------------------------------------------------------------------

from spack import *


class {class_name}({base_class_name}):
    """FIXME: Put a proper description of your package here."""

    # FIXME: Add a proper url for your package's homepage here.
    homepage = "https://www.example.com"
{url_def}

    # FIXME: Add a list of GitHub accounts to
    # notify when the package is updated.
    # maintainers = ['github_user1', 'github_user2']

{versions}

{dependencies}

{body_def}
'''


class BundlePackageTemplate(object):
    """
    Provides the default values to be used for a bundle package file template.
    """

    base_class_name = 'BundlePackage'

    dependencies = """\
    # FIXME: Add dependencies if required.
    # depends_on('foo')"""

    url_def = "    # There is no URL since there is no code to download."
    body_def = "    # There is no need for install() since there is no code."

    def __init__(self, name, versions):
        self.name       = name
        self.class_name = mod_to_class(name)
        self.versions   = versions

    def write(self, pkg_path):
        """Writes the new package file."""

        # Write out a template for the file
        with open(pkg_path, "w") as pkg_file:
            pkg_file.write(package_template.format(
                name=self.name,
                class_name=self.class_name,
                base_class_name=self.base_class_name,
                url_def=self.url_def,
                versions=self.versions,
                dependencies=self.dependencies,
                body_def=self.body_def))


class PackageTemplate(BundlePackageTemplate):
    """Provides the default values to be used for the package file template"""

    base_class_name = 'Package'

    body_def = """\
    def install(self, spec, prefix):
        # FIXME: Unknown build system
        make()
        make('install')"""

    url_line = '    url      = "{url}"'

    def __init__(self, name, url, versions):
        super(PackageTemplate, self).__init__(name, versions)

        self.url_def = self.url_line.format(url=url)


class AutotoolsPackageTemplate(PackageTemplate):
    """Provides appropriate overrides for Autotools-based packages
    that *do* come with a ``configure`` script"""

    base_class_name = 'AutotoolsPackage'

    body_def = """\
    def configure_args(self):
        # FIXME: Add arguments other than --prefix
        # FIXME: If not needed delete this function
        args = []
        return args"""


class AutoreconfPackageTemplate(PackageTemplate):
    """Provides appropriate overrides for Autotools-based packages
    that *do not* come with a ``configure`` script"""

    base_class_name = 'AutotoolsPackage'

    dependencies = """\
    depends_on('autoconf', type='build')
    depends_on('automake', type='build')
    depends_on('libtool',  type='build')
    depends_on('m4',       type='build')

    # FIXME: Add additional dependencies if required.
    # depends_on('foo')"""

    body_def = """\
    def autoreconf(self, spec, prefix):
        # FIXME: Modify the autoreconf method as necessary
        autoreconf('--install', '--verbose', '--force')

    def configure_args(self):
        # FIXME: Add arguments other than --prefix
        # FIXME: If not needed delete this function
        args = []
        return args"""


class CMakePackageTemplate(PackageTemplate):
    """Provides appropriate overrides for CMake-based packages"""

    base_class_name = 'CMakePackage'

    body_def = """\
    def cmake_args(self):
        # FIXME: Add arguments other than
        # FIXME: CMAKE_INSTALL_PREFIX and CMAKE_BUILD_TYPE
        # FIXME: If not needed delete this function
        args = []
        return args"""


class MesonPackageTemplate(PackageTemplate):
    """Provides appropriate overrides for meson-based packages"""

    base_class_name = 'MesonPackage'

    body_def = """\
    def meson_args(self):
        # FIXME: If not needed delete this function
        args = []
        return args"""


class QMakePackageTemplate(PackageTemplate):
    """Provides appropriate overrides for QMake-based packages"""

    base_class_name = 'QMakePackage'

    body_def = """\
    def qmake_args(self):
        # FIXME: If not needed delete this function
        args = []
        return args"""


class MavenPackageTemplate(PackageTemplate):
    """Provides appropriate overrides for Maven-based packages"""

    base_class_name = 'MavenPackage'

    body_def = """\
    def build(self, spec, prefix):
        # FIXME: If not needed delete this function
        pass"""


class SconsPackageTemplate(PackageTemplate):
    """Provides appropriate overrides for SCons-based packages"""

    base_class_name = 'SConsPackage'

    body_def = """\
    def build_args(self, spec, prefix):
        # FIXME: Add arguments to pass to build.
        # FIXME: If not needed delete this function
        args = []
        return args"""


class WafPackageTemplate(PackageTemplate):
    """Provides appropriate override for Waf-based packages"""

    base_class_name = 'WafPackage'

    body_def = """\
    # FIXME: Override configure_args(), build_args(),
    # or install_args() if necessary."""


class BazelPackageTemplate(PackageTemplate):
    """Provides appropriate overrides for Bazel-based packages"""

    dependencies = """\
    # FIXME: Add additional dependencies if required.
    depends_on('bazel', type='build')"""

    body_def = """\
    def install(self, spec, prefix):
        # FIXME: Add logic to build and install here.
        bazel()"""


class PythonPackageTemplate(PackageTemplate):
    """Provides appropriate overrides for python extensions"""
    base_class_name = 'PythonPackage'

    dependencies = """\
    # FIXME: Add dependencies if required. Only add the python dependency
    # if you need specific versions. A generic python dependency is
    # added implicity by the PythonPackage class.
    # depends_on('python@2.X:2.Y,3.Z:', type=('build', 'run'))
    # depends_on('py-setuptools', type='build')
    # depends_on('py-foo',        type=('build', 'run'))"""

    body_def = """\
    def build_args(self, spec, prefix):
        # FIXME: Add arguments other than --prefix
        # FIXME: If not needed delete this function
        args = []
        return args"""

    def __init__(self, name, url, *args, **kwargs):
        # If the user provided `--name py-numpy`, don't rename it py-py-numpy
        if not name.startswith('py-'):
            # Make it more obvious that we are renaming the package
            tty.msg("Changing package name from {0} to py-{0}".format(name))
            name = 'py-{0}'.format(name)

        # Simple PyPI URLs:
        # https://<hostname>/packages/<type>/<first character of project>/<project>/<download file>
        # e.g. https://pypi.io/packages/source/n/numpy/numpy-1.19.4.zip
        # e.g. https://www.pypi.io/packages/source/n/numpy/numpy-1.19.4.zip
        # e.g. https://pypi.org/packages/source/n/numpy/numpy-1.19.4.zip
        # e.g. https://pypi.python.org/packages/source/n/numpy/numpy-1.19.4.zip
        # e.g. https://files.pythonhosted.org/packages/source/n/numpy/numpy-1.19.4.zip

        # PyPI URLs containing hash:
        # https://<hostname>/packages/<two character hash>/<two character hash>/<longer hash>/<download file>
        # e.g. https://pypi.io/packages/c5/63/a48648ebc57711348420670bb074998f79828291f68aebfff1642be212ec/numpy-1.19.4.zip
        # e.g. https://files.pythonhosted.org/packages/c5/63/a48648ebc57711348420670bb074998f79828291f68aebfff1642be212ec/numpy-1.19.4.zip
        # e.g. https://files.pythonhosted.org/packages/c5/63/a48648ebc57711348420670bb074998f79828291f68aebfff1642be212ec/numpy-1.19.4.zip#sha256=141ec3a3300ab89c7f2b0775289954d193cc8edb621ea05f99db9cb181530512

        # PyPI URLs for wheels are too complicated, ignore them for now

        match = re.search(
            r'(?:pypi|pythonhosted)[^/]+/packages' + '/([^/#]+)' * 4,
            url
        )
        if match:
            if len(match.group(2)) == 1:
                # Simple PyPI URL
                url = '/'.join(match.group(3, 4))
            else:
                # PyPI URL containing hash
                # Project name doesn't necessarily match download name, but it
                # usually does, so this is the best we can do
                project = parse_name(url)
                url = '/'.join([project, match.group(4)])

            self.url_line = '    pypi     = "{url}"'

        super(PythonPackageTemplate, self).__init__(name, url, *args, **kwargs)


class RPackageTemplate(PackageTemplate):
    """Provides appropriate overrides for R extensions"""
    base_class_name = 'RPackage'

    dependencies = """\
    # FIXME: Add dependencies if required.
    # depends_on('r-foo', type=('build', 'run'))"""

    body_def = """\
    def configure_args(self):
        # FIXME: Add arguments to pass to install via --configure-args
        # FIXME: If not needed delete this function
        args = []
        return args"""

    def __init__(self, name, url, *args, **kwargs):
        # If the user provided `--name r-rcpp`, don't rename it r-r-rcpp
        if not name.startswith('r-'):
            # Make it more obvious that we are renaming the package
            tty.msg("Changing package name from {0} to r-{0}".format(name))
            name = 'r-{0}'.format(name)

        r_name = parse_name(url)

        cran = re.search(
            r'(?:r-project|rstudio)[^/]+/src' + '/([^/]+)' * 2,
            url
        )

        if cran:
            url = r_name
            self.url_line = '    cran     = "{url}"'

        bioc = re.search(
            r'(?:bioconductor)[^/]+/packages' + '/([^/]+)' * 5,
            url
        )

        if bioc:
            self.url_line = '    url      = "{0}"\n'\
                '    bioc     = "{1}"'.format(url, r_name)

        super(RPackageTemplate, self).__init__(name, url, *args, **kwargs)


class PerlmakePackageTemplate(PackageTemplate):
    """Provides appropriate overrides for Perl extensions
    that come with a Makefile.PL"""
    base_class_name = 'PerlPackage'

    dependencies = """\
    # FIXME: Add dependencies if required:
    # depends_on('perl-foo', type=('build', 'run'))"""

    body_def = """\
    def configure_args(self):
        # FIXME: Add non-standard arguments
        # FIXME: If not needed delete this function
        args = []
        return args"""

    def __init__(self, name, *args, **kwargs):
        # If the user provided `--name perl-cpp`, don't rename it perl-perl-cpp
        if not name.startswith('perl-'):
            # Make it more obvious that we are renaming the package
            tty.msg("Changing package name from {0} to perl-{0}".format(name))
            name = 'perl-{0}'.format(name)

        super(PerlmakePackageTemplate, self).__init__(name, *args, **kwargs)


class PerlbuildPackageTemplate(PerlmakePackageTemplate):
    """Provides appropriate overrides for Perl extensions
    that come with a Build.PL instead of a Makefile.PL"""
    dependencies = """\
    depends_on('perl-module-build', type='build')

    # FIXME: Add additional dependencies if required:
    # depends_on('perl-foo', type=('build', 'run'))"""


class OctavePackageTemplate(PackageTemplate):
    """Provides appropriate overrides for octave packages"""

    base_class_name = 'OctavePackage'

    dependencies = """\
    extends('octave')

    # FIXME: Add additional dependencies if required.
    # depends_on('octave-foo', type=('build', 'run'))"""

    def __init__(self, name, *args, **kwargs):
        # If the user provided `--name octave-splines`, don't rename it
        # octave-octave-splines
        if not name.startswith('octave-'):
            # Make it more obvious that we are renaming the package
            tty.msg("Changing package name from {0} to octave-{0}".format(name))  # noqa
            name = 'octave-{0}'.format(name)

        super(OctavePackageTemplate, self).__init__(name, *args, **kwargs)


class RubyPackageTemplate(PackageTemplate):
    """Provides appropriate overrides for Ruby packages"""

    base_class_name = 'RubyPackage'

    dependencies = """\
    # FIXME: Add dependencies if required. Only add the ruby dependency
    # if you need specific versions. A generic ruby dependency is
    # added implicity by the RubyPackage class.
    # depends_on('ruby@X.Y.Z:', type=('build', 'run'))
    # depends_on('ruby-foo', type=('build', 'run'))"""

    body_def = """\
    def build(self, spec, prefix):
        # FIXME: If not needed delete this function
        pass"""

    def __init__(self, name, *args, **kwargs):
        # If the user provided `--name ruby-numpy`, don't rename it
        # ruby-ruby-numpy
        if not name.startswith('ruby-'):
            # Make it more obvious that we are renaming the package
            tty.msg("Changing package name from {0} to ruby-{0}".format(name))
            name = 'ruby-{0}'.format(name)

        super(RubyPackageTemplate, self).__init__(name, *args, **kwargs)


class MakefilePackageTemplate(PackageTemplate):
    """Provides appropriate overrides for Makefile packages"""

    base_class_name = 'MakefilePackage'

    body_def = """\
    def edit(self, spec, prefix):
        # FIXME: Edit the Makefile if necessary
        # FIXME: If not needed delete this function
        # makefile = FileFilter('Makefile')
        # makefile.filter('CC = .*', 'CC = cc')"""


class IntelPackageTemplate(PackageTemplate):
    """Provides appropriate overrides for licensed Intel software"""

    base_class_name = 'IntelPackage'

    body_def = """\
    # FIXME: Override `setup_environment` if necessary."""


class SIPPackageTemplate(PackageTemplate):
    """Provides appropriate overrides for SIP packages."""

    base_class_name = 'SIPPackage'

    body_def = """\
    def configure_args(self, spec, prefix):
        # FIXME: Add arguments other than --bindir and --destdir
        # FIXME: If not needed delete this function
        args = []
        return args"""

    def __init__(self, name, *args, **kwargs):
        # If the user provided `--name py-pyqt4`, don't rename it py-py-pyqt4
        if not name.startswith('py-'):
            # Make it more obvious that we are renaming the package
            tty.msg("Changing package name from {0} to py-{0}".format(name))
            name = 'py-{0}'.format(name)

        super(SIPPackageTemplate, self).__init__(name, *args, **kwargs)


templates = {
    'autotools':  AutotoolsPackageTemplate,
    'autoreconf': AutoreconfPackageTemplate,
    'cmake':      CMakePackageTemplate,
    'bundle':     BundlePackageTemplate,
    'qmake':      QMakePackageTemplate,
    'maven':      MavenPackageTemplate,
    'scons':      SconsPackageTemplate,
    'waf':        WafPackageTemplate,
    'bazel':      BazelPackageTemplate,
    'python':     PythonPackageTemplate,
    'r':          RPackageTemplate,
    'perlmake':   PerlmakePackageTemplate,
    'perlbuild':  PerlbuildPackageTemplate,
    'octave':     OctavePackageTemplate,
    'ruby':       RubyPackageTemplate,
    'makefile':   MakefilePackageTemplate,
    'intel':      IntelPackageTemplate,
    'meson':      MesonPackageTemplate,
    'sip':        SIPPackageTemplate,
    'generic':    PackageTemplate,
}


def setup_parser(subparser):
    subparser.add_argument(
        'url', nargs='?',
        help="url of package archive")
    subparser.add_argument(
        '--keep-stage', action='store_true',
        help="don't clean up staging area when command completes")
    subparser.add_argument(
        '-n', '--name',
        help="name of the package to create")
    subparser.add_argument(
        '-t', '--template', metavar='TEMPLATE',
        choices=sorted(templates.keys()),
        help="build system template to use. options: %(choices)s")
    subparser.add_argument(
        '-r', '--repo',
        help="path to a repository where the package should be created")
    subparser.add_argument(
        '-N', '--namespace',
        help="specify a namespace for the package. must be the namespace of "
        "a repository registered with Spack")
    subparser.add_argument(
        '-f', '--force', action='store_true',
        help="overwrite any existing package file with the same name")
    subparser.add_argument(
        '--skip-editor', action='store_true',
        help="skip the edit session for the package (e.g., automation)")
    subparser.add_argument(
        '-b', '--batch', action='store_true',
        help="don't ask which versions to checksum")


class BuildSystemGuesser:
    """An instance of BuildSystemGuesser provides a callable object to be used
    during ``spack create``. By passing this object to ``spack checksum``, we
    can take a peek at the fetched tarball and discern the build system it uses
    """

    def __init__(self):
        """Sets the default build system."""
        self.build_system = 'generic'

    def __call__(self, stage, url):
        """Try to guess the type of build system used by a project based on
        the contents of its archive or the URL it was downloaded from."""

        if url is not None:
            # Most octave extensions are hosted on Octave-Forge:
            #     https://octave.sourceforge.net/index.html
            # They all have the same base URL.
            if 'downloads.sourceforge.net/octave/' in url:
                self.build_system = 'octave'
                return
            if url.endswith('.gem'):
                self.build_system = 'ruby'
                return

        # A list of clues that give us an idea of the build system a package
        # uses. If the regular expression matches a file contained in the
        # archive, the corresponding build system is assumed.
        # NOTE: Order is important here. If a package supports multiple
        # build systems, we choose the first match in this list.
        clues = [
            (r'/CMakeLists\.txt$',    'cmake'),
            (r'/NAMESPACE$',          'r'),
            (r'/configure$',          'autotools'),
            (r'/configure\.(in|ac)$', 'autoreconf'),
            (r'/Makefile\.am$',       'autoreconf'),
            (r'/pom\.xml$',           'maven'),
            (r'/SConstruct$',         'scons'),
            (r'/waf$',                'waf'),
            (r'/setup\.py$',          'python'),
            (r'/WORKSPACE$',          'bazel'),
            (r'/Build\.PL$',          'perlbuild'),
            (r'/Makefile\.PL$',       'perlmake'),
            (r'/.*\.gemspec$',        'ruby'),
            (r'/Rakefile$',           'ruby'),
            (r'/setup\.rb$',          'ruby'),
            (r'/.*\.pro$',            'qmake'),
            (r'/(GNU)?[Mm]akefile$',  'makefile'),
            (r'/DESCRIPTION$',        'octave'),
            (r'/meson\.build$',       'meson'),
            (r'/configure\.py$',      'sip'),
        ]

        # Peek inside the compressed file.
        if (stage.archive_file.endswith('.zip') or
                '.zip#' in stage.archive_file):
            try:
                unzip  = which('unzip')
                output = unzip('-lq', stage.archive_file, output=str)
            except ProcessError:
                output = ''
        else:
            try:
                tar    = which('tar')
                output = tar('--exclude=*/*/*', '-tf',
                             stage.archive_file, output=str)
            except ProcessError:
                output = ''
        lines = output.split('\n')

        # Determine the build system based on the files contained
        # in the archive.
        for pattern, bs in clues:
            if any(re.search(pattern, line) for line in lines):
                self.build_system = bs
                break


def get_name(args):
    """Get the name of the package based on the supplied arguments.

    If a name was provided, always use that. Otherwise, if a URL was
    provided, extract the name from that. Otherwise, use a default.

    Args:
        args (param argparse.Namespace): The arguments given to
            ``spack create``

    Returns:
        str: The name of the package
    """

    # Default package name
    name = 'example'

    if args.name is not None:
        # Use a user-supplied name if one is present
        name = args.name
        if len(args.name.strip()) > 0:
            tty.msg("Using specified package name: '{0}'".format(name))
        else:
            tty.die("A package name must be provided when using the option.")
    elif args.url is not None:
        # Try to guess the package name based on the URL
        try:
            name = parse_name(args.url)
            if name != args.url:
                desc = 'URL'
            else:
                desc = 'package name'
            tty.msg("This looks like a {0} for {1}".format(desc, name))
        except UndetectableNameError:
            tty.die("Couldn't guess a name for this package.",
                    "  Please report this bug. In the meantime, try running:",
                    "  `spack create --name <name> <url>`")

    name = simplify_name(name)

    if not valid_fully_qualified_module_name(name):
        tty.die("Package name can only contain a-z, 0-9, and '-'")

    return name


def get_url(args):
    """Get the URL to use.

    Use a default URL if none is provided.

    Args:
        args (argparse.Namespace): The arguments given to ``spack create``

    Returns:
        str: The URL of the package
    """

    # Default URL
    url = 'https://www.example.com/example-1.2.3.tar.gz'

    if args.url:
        # Use a user-supplied URL if one is present
        url = args.url

    return url


def get_versions(args, name):
    """Returns a list of versions and hashes for a package.

    Also returns a BuildSystemGuesser object.

    Returns default values if no URL is provided.

    Args:
        args (argparse.Namespace): The arguments given to ``spack create``
        name (str): The name of the package

    Returns:
        str and BuildSystemGuesser: Versions and hashes, and a
            BuildSystemGuesser object
    """

    # Default version with hash
    hashed_versions = """\
    # FIXME: Add proper versions and checksums here.
    # version('1.2.3', '0123456789abcdef0123456789abcdef')"""

    # Default version without hash
    unhashed_versions = """\
    # FIXME: Add proper versions here.
    # version('1.2.4')"""

    # Default guesser
    guesser = BuildSystemGuesser()

    if args.url is not None and args.template != 'bundle':
        # Find available versions
        try:
            url_dict = spack.util.web.find_versions_of_archive(args.url)
        except UndetectableVersionError:
            # Use fake versions
            tty.warn("Couldn't detect version in: {0}".format(args.url))
            return hashed_versions, guesser

        if not url_dict:
            # If no versions were found, revert to what the user provided
            version = parse_version(args.url)
            url_dict = {version: args.url}

        versions = spack.stage.get_checksums_for_versions(
            url_dict, name, first_stage_function=guesser,
            keep_stage=args.keep_stage,
            batch=(args.batch or len(url_dict) == 1))
    else:
        versions = unhashed_versions

    return versions, guesser


def get_build_system(args, guesser):
    """Determine the build system template.

    If a template is specified, always use that. Otherwise, if a URL
    is provided, download the tarball and peek inside to guess what
    build system it uses. Otherwise, use a generic template by default.

    Args:
        args (argparse.Namespace): The arguments given to ``spack create``
        guesser (BuildSystemGuesser): The first_stage_function given to
            ``spack checksum`` which records the build system it detects

    Returns:
        str: The name of the build system template to use
    """
    # Default template
    template = 'generic'

    if args.template is not None:
        # Use a user-supplied template if one is present
        template = args.template
        tty.msg("Using specified package template: '{0}'".format(template))
    elif args.url is not None:
        # Use whatever build system the guesser detected
        template = guesser.build_system
        if template == 'generic':
            tty.warn("Unable to detect a build system. "
                     "Using a generic package template.")
        else:
            msg = "This package looks like it uses the {0} build system"
            tty.msg(msg.format(template))

    return template


def get_repository(args, name):
    """Returns a Repo object that will allow us to determine the path where
    the new package file should be created.

    Args:
        args (argparse.Namespace): The arguments given to ``spack create``
        name (str): The name of the package to create

    Returns:
        Repo: A Repo object capable of determining the path to the package file
    """
    spec = Spec(name)
    # Figure out namespace for spec
    if spec.namespace and args.namespace and spec.namespace != args.namespace:
        tty.die("Namespaces '{0}' and '{1}' do not match.".format(
            spec.namespace, args.namespace))

    if not spec.namespace and args.namespace:
        spec.namespace = args.namespace

    # Figure out where the new package should live
    repo_path = args.repo
    if repo_path is not None:
        repo = spack.repo.Repo(repo_path)
        if spec.namespace and spec.namespace != repo.namespace:
            tty.die("Can't create package with namespace {0} in repo with "
                    "namespace {1}".format(spec.namespace, repo.namespace))
    else:
        if spec.namespace:
            repo = spack.repo.path.get_repo(spec.namespace, None)
            if not repo:
                tty.die("Unknown namespace: '{0}'".format(spec.namespace))
        else:
            repo = spack.repo.path.first_repo()

    # Set the namespace on the spec if it's not there already
    if not spec.namespace:
        spec.namespace = repo.namespace

    return repo


def create(parser, args):
    # Gather information about the package to be created
    name = get_name(args)
    url = get_url(args)
    versions, guesser = get_versions(args, name)
    build_system = get_build_system(args, guesser)

    # Create the package template object
    constr_args = {'name': name, 'versions': versions}
    package_class = templates[build_system]
    if package_class != BundlePackageTemplate:
        constr_args['url'] = url
    package = package_class(**constr_args)
    tty.msg("Created template for {0} package".format(package.name))

    # Create a directory for the new package
    repo = get_repository(args, name)
    pkg_path = repo.filename_for_package_name(package.name)
    if os.path.exists(pkg_path) and not args.force:
        tty.die('{0} already exists.'.format(pkg_path),
                '  Try running `spack create --force` to overwrite it.')
    else:
        mkdirp(os.path.dirname(pkg_path))

    # Write the new package file
    package.write(pkg_path)
    tty.msg("Created package file: {0}".format(pkg_path))

    # Optionally open up the new package file in your $EDITOR
    if not args.skip_editor:
        editor(pkg_path)
